Abstract

Continuously variable time compression, expansion, and inversion, with the corresponding changes in frequency, of rf signals in the range of 10 to 100 MHz, are described. By using a simple optical heterodyning technique and high‐speed scanning of a laser beam, an rf signal, ``stored'' as an acoustic signal in a quartz bar, can be processed or ``read out'' in a variety of ways. Although present equipment has limited the amount of processing and frequency range of the signals that can be handled, it is felt that input signal frequencies are restricted only by the acoustic properties of the delay medium and the output frequencies will be limited by the response of the photodetector.